Just before the supercool all-black ship crashes into a sun, Zaphod, Trillian, Ford, and Arthur escape in a teleport module that they convince Marvin to stay behind and operate. He is still on the ship when it heads into the sun. Ford and Arthur arrive - without Zaphod and Trillian - on a spaceship carrying millions of people in cryogenic pods. The ship's inhabitants are from Golgafrincham; they are unskilled workers in apparently pointless jobs, the people that the clever Golgafrinchams, the thinkers and the doers, back home wanted to get rid of.
The ship lands on pre-historic Earth. Ford realises that the Golgafrinchams, not the primitive cave dwellers already on the planet, are the ones that will evolve into the human race. The episode ends with the two friends lamenting the eventual destruction of the Earth.